Hey guys, just wondering if it's actually possible to check if my primaries are working without pulling off the throttle body and upper intake manifold. The FSM and Haynes both suggest using a mechanic's stethoscope, and while I could see that working for the secondaries I just can't figure out how I'd get at the primaries while they're tucked up under the manifold.

 

Yes, you can check. Two methods which can be easily done in the driveway:

1. Stethoscope as you suggest. The type with the long rod (hehe) that transmits sound. With some light, you will be able to just see the tops of the injectors. I've used this method to diagnose many times.

2. Try the fire test. Remove the trailing spark plugs and disconnect the trailing coil power connection (as to not stress the coil). Crank the engine. The side of the engine not shooting fire from the trailing hole probably doesn't have a working primary injector. Don't run the engine like this (if it will, sometimes it might).

 

if you're familure with your car enough to set the timing you can leave the key ON and remove the CAS( crank sensor) and spin it , this will pulse the injectors without all the other noises of the starter/ engine compression... and it won't crank.... you just have to put the CAS back in timing which is not for everybody.